Modular ships Mojo 1.0 with stable language core and MAX 26.5

Modular has released Mojo 1.0, the first stable version of its systems programming language, alongside the 26.5 update to MAX, its AI infrastructure platform. The company says the language is now production-ready and will be the foundation of its commercial products, including MAX and Modular Cloud.

Mojo 1.0 follows a period of rapid change that made it hard for external developers to maintain long-term projects. The release converges on a single way to express common ideas: variables are consistently declared with var, closures are unified, and there is one Pointer type. The company says this final round of simplification gives developers a stable base for building libraries and applications.

New features in Mojo 1.0

The release adds Python-style lambda syntax for inline closures, a more stable LSP server for editors like VS Code, and improved diagnostics for memory safety issues such as reference invalidation when calling List.append. The Mojo AI Skills are now described as "1.0 ready," covering project creation, GPU programming, and porting from other languages. The standard library also uses where clauses more consistently, with descriptive error messages.

Modular says the 1.x timeframe will be primarily additive, with breaking changes managed carefully, following the example of mature languages like C++. The company also reaffirmed its commitment to open-sourcing the Mojo compiler and toolchain in 2026.

MAX 26.5 updates

MAX 26.5 adds support for two new model families: GLM-5.2 and Nemotron-H, both hybrid Mamba-2 models. Kimi 2.5 now works with Module V3, Modular's streamlined model-authoring path. Installation is simpler: users can install only the dependencies they need with options like max["serve"] and max["benchmark"], or max["all"] for everything. The modular package will be retired in 26.6.

Modular also highlighted its open source agent skills, which it says have been used internally to speed up full model lifecycle bring-up and have seen 7.2K+ downloads through skills.sh.

Mojo 1.0 and MAX 26.5 are available now. Modular will discuss its plans for Mojo, MAX, and open source at ModCon on August 18 in San Francisco.